Straight or curly hair, abundant or almost non-existent, being gray or eyebrow … according to a new study carried out by an international team of scientists in which the University of Oviedo (Spain) collaborates, it has discovered that these characteristics of the hair depend on so far not very well defined genetic factors. Thus, experts have managed to identify the first gene responsible for gray hair and being a single eye. The study has been published in the journal Nature Communications.
To reach this conclusion, the scientists analyzed the genome of a sample of 6,357 volunteers from five South American countries with different ancestral genetic makeup in order to identify those genes associated with color, density, hair shape and also facial hair. The examination of this genetic diversity resulted in the discovery of 10 genetic variants that influence the appearance of our hair, including the IRF4 gene, key in the appearance of gray hair and also responsible for the fact that both eyebrows are united.
“Several genes involved in baldness and hair color were already known, but this is the first time that a gene associated with white hair in humans has been identified, as well as others associated with shape and density,” says Kaustubh Adhikari, study leader.
Gray hair appears due to the absence of melanin in the hair (the pigment that marks what color hair, skin and eyes we have) and precisely the IRF4 gene is in charge of regulating the production and storage of melanin. According to experts, this genetic association could be key to the development of treatments that delay the appearance of gray hair, for example.
According to Adhikari, this analysis supports the idea that hair characteristics are defined by natural or sexual selection: It is unlikely that the identified genes work separately to cause graying, straight hair or thick eyebrows . These must play a joint role with many other factors yet to be identified ”, he comments.





